The present invention generally relates to wireless electronic communication devices and, but not by way of limitation, to mobile phones.
Wireless communication electronic devices, such as a mobile phone, or a tablet are known devices. These devices mainly consist of a transceiver, a display, a keyboard, and an antenna. Antennas used in electronic devices generate electromagnetic radiation to some extent absorbed by living tissues, which is measured by SAR factor. The radiation adversely affects the health of the user of the device.
In known wireless electronic communication devices, the antenna is positioned generally at the outer perimeter edge of the casing and is directly surrounded by the casing made of a non-conducting material, usually plastic. Because of the placement of antenna directly under the casing, at a place where the casing is in a direct contact with the face of the user, the absorption of radiation with a large absorption rate, by the user, may take place quickly. For this reason, radiation of the antenna can directly affect the health of the user when using the device, especially when making phone calls through the device.
In other known electronic communication devices the casings are made of metal, in particular aluminium. These devices use slot antennas, where the antenna is placed under the casing on one of the poles of the device and the slot allows for the emission of radiation being performed in the casing at the opposite pole. The disadvantage of this solution is that the slot is made in the casing in an area where the user holds the device during usage, which means, once again, the radiation directly reaches the user. Another disadvantage of this solution is that the placement of antenna in a metal casing will substantially deteriorate the characteristics of omnidirectional antennas. This disadvantage is further compounded by the fact that the entire device may become an antenna. This is due to the fact that the dimensions of the antenna are much smaller than the wavelength of its operating frequency. In this situation, the antenna should be treated as a radiating element close to a point source, which may be reinforced by the metal casing.
Embodiments of the present invention provide solutions for limiting the extent of absorption of radiation generated by the radio wave antennas used in electronic communication devices. The invention also relates to improving the characteristics of omnidirectional antennas working in electronic telecommunication devices.